1. Field of the Invention
This invention pertains to improved denture adhesive compositions which provide superior adhesion properties. More particularly, this invention pertains to denture adhesive compositions which comprise an adhesive component comprising a mixture of a mixed, partial calcium/sodium salt of a methyl vinyl ether-maleic anhydride-type copolymer and sodium carboxymethylcellulose, a vehicle component comprising a mixture of petrolatum and mineral oil, and a hydration and tackifier component comprising silicon dioxide and poly(ethylene oxide) homopolymer. This invention also pertains to methods by which these improved denture adhesive compositions may be prepared.
2. Description of the Prior Art
Denture adhesive compositions are generally prepared from natural or synthetic polymeric materials suspended in an oleaginous vehicle system. Upon contact with water, these polymeric materials have the property of swelling to several times their original volume to form a gelatinous mass which can fill the space, act as a cushion and provide adhesion between a denture plate and gum tissue.
Some commonly noted deficiencies with denture adhesive compositions are phase separation of the adhesive composition, the need for more than one application of the adhesive composition per day and oozing of the adhesive composition from under the denture plate. Phase separation of the adhesive composition causes loss of the oily vehicle component which results in an excessively thick denture adhesive composition. Multiple applications of the adhesive composition are generally undesirable. Oozing of the denture adhesive composition from under the denture plate, usually the result of excessive swelling of the adhesive composition during hydration, is a major drawback because of the resulting unplesant taste, unpleasant mouth feel and loss of adhesive composition from under the denture plate. Insufficient swelling of the denture adhesive composition, on the other hand, results in an adhesive composition which provides insufficient space filling and cushioning properties under the denture plate.
U.S. Pat. No. 2,978,812, issued to Rosenthal et al. and assigned to Block Drug Company, Inc., discloses the use of poly(ethylene oxide) homopolymer as a denture adhesive. When wetted, the poly(ethylene oxide) homopolymer is said to form a gel which has a high degree of tackiness.
U.S. Pat. No. 3,003,988, issued to Germann et al. and assigned to Clark-Cleveland Incorporated, discloses the use of mixed, partial salts of lower alkyl vinyl of ether-maleic anhydride-type copolymers as water-sensitized, water-insoluble denture stabilizers.
U.S. Pat. No. 3,380,876, issued to Rusher and assigned to E. I. duPont de Nemours and Company, discloses the use of colloidal silicon dioxide particles containing a minor amount of an organic additive to bond thermoplastic materials to a substrate. The organic additive is selected from the group consisting of polyethylene glycol, tert-dodecylthioether, polyoxyethylene sorbitan monolaurate and water-soluble resins of poly(ethylene oxide) homopolymer.
U.S. Pat. No. 3,736,274, issued to Schoenholz et al. and assigned to Foremost-McKesson, Inc., discloses a denture adhesive composition comprised of (a) a polymeric material selected from the group consisting of lower alkyl vinyl ether-maleic anhydride and/or acid-type copolymers, (b) a polymeric N-vinyl lactam, and (c) sodium carboxymethylcellulose.
U.S. Pat. No. 4,514,528, issued to Dhabhar et al. and assigned to Richardson-Vicks Inc., discloses a hydrophilic denture adhesive composition comprising an adhesive polymeric fraction consisting essentially of mixed, partial salts of lower alkyl vinyl ether-maleic anhydride-type copolymers with sodium carboxymethylcellulose and/or poly(ethylene oxide) homopolymer and a vehicle fraction comprising polyethylene glycol.
U.S. Pat. No. 4,518,721, issued to Dhabhar et al. and assigned to Richardson-Vicks Inc., discloses a hydrophilic denture adhesive composition consisting essentially of sodium carboxymethylcellulose and poly(ethylene oxide) homopolymer in a hydrophilic vehicle comprising polyethylene glycol.
U.S. Pat. No. 4,522,956, issued to Dhabhar et al. and assigned to Richardson-Vicks Inc., discloses a hydrophilic denture adhesive composition consisting essentially of poly(ethylene oxide) homopolymer as the adhesive component and polyethylene glycol as the vehicle component.
U.S. Pat. No. 4,530,942, issued to Dhabhar et al. and assigned to Richardson-Vicks Inc., discloses a hydrophilic denture adhesive composition consisting essentially of sodium carboxymethylcellulose as the adhesive component and polyethylene glycol as the hydrophilic vehicle component.
U.S. Pat. No. 4,569,955, issued to Dhabhar and assigned to Richardson-Vicks Inc., discloses a denture adhesive composition consisting essentially of an adhesive polymeric fraction consisting essentially of a mixed, partial salt of a lower alkyl vinyl ether-maleic anhydride-type copolymer and sodium carboxymethylcellulose in a vehicle component consisting essentially of mineral oil thickened with polyethylene.
European patent application EPO No. 265 916 A2, assigned to Richardson-Vicks Inc., discloses a denture stabilizing composition which contains unmixed, partial zinc and strontium salts of lower alkyl vinyl ether-maleic acid type copolymers.
While all of the above denture adhesive compositions provide some degree of denture stability, none of the above products can accommodate the many variations in temperature, pH and mechanical agitation which are normal in the oral cavity over a prolonged period of time. Hence, there is still a need for denture adhesive compositions which have superior adhesive properties over prolonged periods of time. The present invention provides such improved denture adhesive compositions with superior adhesive properties over prolonged periods of time and under varied conditions without the organoleptic disadvantages characteristic of previously known products. The present invention also provides methods by which these improved denture adhesive compositions may be prepared.